Connector arrangement for coaxial conductors



April 24, 1962 T. LOCK 3,031,636

CONNECTOR ARRANGEMENT FOR COAXIAL CONDUCTORS Filed July 22, 1960 Iuvmron jhm ZM gint 4rd United States Patent O CONNECTOR ARRANGEMENT FOR COAXIAL CONDUCTORS Tom Lock, Northampton, England, assignor to Associated Electrical Industries Limited, London, England, a British company Filed July 22, 1960, Ser. No. 44,731

Claims priority, application Great Britain Aug. 7, 1959 1 Claim. (Cl. 339-89) This invention relates to coaxial conductors and aims at providing an improved connecting arrangement suitable to maintain a high insulation and breakdown value, substantially independent of external conditions such as humidity of the surrounding atmosphere, and also of the ionisation in a possible air gap.

This is achieved by providing an effective means for sealing the space about the ends of the inner conductors of two coaxial conductor pairs.

Accordingly the invention resides in a connector for two coaxial conductor pairs wherein the end of an insulation covering the inner conductor of one of the pairs is shaped conically and an insert of insulating material is positioned between the ends of the insulations covering the inner conductors of the two coaxial conductor pairs, said insert having an annular zone for matching in engagement an annular zone of said conically shaped end surface, at least one of the two zones being resilient, and a means being provided for pressing the two zones together to produce a sealing eect.

Advantageously the base of the conical sealing end has an outer diameter which is greater than that of a cylindrical insulating coating provided on the inner conductor, and forms a unitary insulation with the cylindrical coatlng.

In an embodiment as preferred at present the material of the insulation is polytetrafluoroethylene, and the shape of the unitary insulation is formed by a moulding process.

The invention is applicable to constructions of coaxial conductors, which are otherwise conventional, but is particularly advantageous in conjunction with coaxial cables having a metal braiding as the outer conductor. The invention will now be explained in greater detail with reference to the single FIGURE of the accompanying drawing the upper half of which is a plan view and the lower half of which is a sectional view of such a preferred embodiment of the invention.

Referring to the drawing each one of the coaxial cables comprises an inner conductor 9, 9', separated by an insulating coating I, I', such as of polytetrafluoroethylene moulded thereto, from an outer conductor 1, 1' comprising a metal braiding. The end of the inner conductor 9e is bared and is soldered into a recess of an intermediate contact piece 4 of metal. At the other end of the contact piece 4 a recess is provided for the detachable' connection of the end 9e of the inner conductor 9'. A conical surface 11 is formed at the end of the insulation I', preferably by a method which will be described later, and an insert 6 of insulating material which may be different from, but is preferably similar to, the material of the coatings I, I', is arranged between the insulations I, I', the right-hand end of the insert 6 being shaped to engage an annular zone of the conical surface 11.

Metal ferrules 2, 2' are secured to end portions of the insulations I, I. The left-hand end of the insert 6 is also secured to the ferrule 2. In a preferred embodiment the outer surface of the portion of the contact member 4 surrounding the conductor end 9e is roughened or ribbed at and a swaging process is used to secure the ferrule 2 to the insulation I and the contact member 4. In this manner the solder joint between the conductor end 9e and the contact member 4 is relieved from stress when the conductor end 9e is withdrawn from the recess in the contact member 4.

In order to produce a suitable sealing pressure between the parts 6 and 11 the ferrule 2 is provided with an outer screw thread 8 to engage an inner screw thread of a casing 3, having an opening at the other end OE, which is turned in to engage a shoulder on the ferrule 2. The casing 3 is slipped over the left-hand coaxial conductor pair before the ferrule 2 is swaged on. Preferably the screw threaded part is short to facilitate rapid coupling and decoupling of the two coaxial ends. A shoulder SH can be provided on the inner surface of the casing 3, and a Washer 5 of resilient material can be held under pressure between this shoulder and the end of the ferrule 2 in order to provide an additional seal.

It will be understood that the insulating material forming the conical surface 11 must be tightly joined to the insulator I of the coaxial conductor pair, and this can be best achieved by forming the cone from the cylindrical insulating coating already provided on the inner conductor, such as a copper wire coated with polytetrafluoroethylene. Means for achieving this may comprise a pair of flat fingers for gripping the insulating coating of the wire at a short distance from the wire end, and a moulding tool which has a conical recess corresponding to the shape of the surface 11, also, a central bore for receiving the wire when the heated moulding tool is moved towards the gripping lingers thereby to form a conical end on the insulating I from the insulating wire coating. The length of coated wire between the wire end and the gripping fingers is so chosen that the quantity of insulating material which is removed from the wire end 9e when the moulding tool advances is just sufficient to fill the conical recess in the moulding tool.

While a preferred embodiment of the invention has been described in greater detail it will be understood that variations are possible without departing from the invention.

What I claim is:

A connector for two coaxial conductor pairs having the end of an insulation covering of the inner conductor of one of the pairs shaped conically, having a hollow cylinder insert of insulating material extending from the insulation covering adjacent the end of the inner conductor of the other pair to an annular zone of said conically shaped insulation end of said one conductor pair, a metal insert being fixed to the end of the inner conductor of the said other conductor pair and having a recess for detachably engaging a projecting end of the inner conductor of said one conductor pair, a metal ferrule being conductively connected to the outer conductor of the said other pair, and being secured to the outside of the insulation of the inner conductor of said other conductor pair, also to the outside of the said insulating insert, the latter having one end of its inner wall secured to the outer cylindrical surface of the metal insert, also including a second metal ferrule conductively connected to the outer conductor of said one conductor pair, a shoulder being provided on said first ferrule, a casing being provided to engage rotatably said shoulder, and matching screw threads being arranged on the outside of said second ferrule and inside of said casing to engage with each other.

References Cited in the file of this patent UNITED STATES PATENTS (Other references on following page) 3 UNITED STATES PATENTS Devol Sept. 28, 1948 Warren Oct. 26, 1948 Gutterman Apr. 17, 1951 De Packh et a1 June 9, 1953 Bowar Iune 16, 1953 Allan Oct. 13, 1953 Salisbury Mar. 23, 1954 Dupre et a1. June 7, 1955 Watters et a1 Nov. 11, 1958 FOREIGN PATENTS Great Britain Oct. 30, 1957 

